DNA Hybridisation and Immunological comparisons of proteins Flashcards
(14 cards)
What are changes in DNA caused by
Mutations
How can DNA be used to tell how closely related two or more organisms are
The more differences there are the less closely related two species are as they will have evolved separately for a longer period of time.
What is step 1 of DNA hybridisation
DNA from 2 species is extracted, purified & cut into small pieces
What is step 2 of DNA hybridisation
DNA is heated to about 90°C to break the H bonds
What is step 3 of DNA hybridisation
On cooling, the strands combine with others that have a complementary base sequence. The more similar, the more H bonds.
What is step 4 of DNA hybridisation
To separate the strands again they are heated. The higher the temperature needed to break the strands apart = more H bonds. Therefore the more closely related the species.
Give an example of when DNA hybridisation can be used
To aid in the classification of flowering plants
Explain the concept of immunological comparisons of proteins
Using the body’s immune system to analyse and compare the structures of proteins from different species, antibodies of one species will respond to antigens on proteins in the blood serum of another.
What is step 1 of the immunological comparison method
Serum albumin from Sp. A injected into Sp. B
What is step 2 of the immunological comparison method
Sp. B produces antibodies specific to all the antigen sites on Sp. A albumin
What is step 3 of the immunological comparison method
Serum is extracted from Sp. B; containing antibodies specific to antigens on Sp. A’s albumin
What is step 4 of the immunological comparison method
Serum from Sp. B is mixed with blood from a third species, Sp. C
What is step 5 of the immunological comparison method
Antibodies respond to antigens on albumin of Sp. C - Response is the formation of a precipitate
What is step 6 of the immunological comparison method
More similar antigens, more precipitate formed and more closely related the species
